Straightening machine and method



July 7, 1970 D. A. CARGILL 3,518,868

STRAIGHTENING MACHINE AND METHOD Filed Jan. 11, 1968 10 Sheets-Sheet 1 I NVENTOR 00% 14. (4.66/41 ATTORNEYS July 7, 1970 D. A. CARGILL STRAIGHTENING MACHINE AND METHOD l0 Sheets-Sheet 2 Filed Jan. 11, 1968 N 0 TL INVENTOR 00/1/ ,4. (3486/11 ATTORNEYS July 7, 1970 CARGILL 3,518,868

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STRAIGHTENING MACHINE AND METHOD Filed Jan. 11, 1968 10 Sheets-Sheet 1O INVENTOR 004 /4. (3436/11 ATTO RNEYS United States Patent 3,518,868 STRAIGHTENING MACHINE AND METHOD Don A. Cargill, 822 Fairfax, Birmingham, Mich. 48009 Filed Jan. 11, 1968, Ser. No. 697,076 Int. Cl. B21d 3/00 US. Cl. 72-389 18 Claims ABSTRACT OF THE DISCLOSURE A straightening machine and method in which a central portion of the neutral axis of a work piece is deflected beyond yield point in a gradually diminishing orbital path while the ends are restrained against radial movement including a crank arm clamped at one end to the work piece and at the other end to a crankshaft having a variable eccentric actuated by cam and roller elements through axial shifting of an hydraulic cylinder piston rod between maximum and zero eccentric positions and an intermediate bearing guide for the crank arm trans lating the variable eccentric movement at the crankshaft to a corresponding orbital movement of the work piece axis without rotation of the work piece about its own axis.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to straightening machines and methods for correcting work pieces having distorted neutral axes through cyclical deflection of the neutral axis in an orbital path centered on the true neutral axis. Increase of deflection to an amplitude extending through the yield point of a work piece having a true neutral axis is relied upon to stress beyond yield point a distorted work piece in the direction required to straighten the neutral axis and gradual relaxation of the deflection through reduction of the orbital displacement is relied upon to automatically straighten within a predetermined tolerance limitation. More particularly the present invention is adapted to impart such orbital deflection without rotation of the work piece about its own axis while confining longitudinally spaced portions of the work piece from radial displacement of the neutral axis.

Description of the prior art Deflection relaxation straightening has been applied to rotatable shafts and rings by deflecting the work piece during rotation through the normal yield point followed by gradual relaxation of the deflection. While this technique is suitable for cylindrical work pieces having no irregularities in the area of applying deflection forces or holding forces there are many elongated work pieces having a neutral axis which do not have convenient cylindrical surfaces for applying deflection and/or holding forces during rotation for which the present invention may be readily adapted.

SUMMARY OF THE INVENTION In a preferred embodiment the machine of the present invention employs a crank arm one end of which may be rigidly clamped to a work piece intermediate its length, for example centrally of its longitudinal neutral axis, While the ends of the Work piece are held in spherical bearings restraining radial displacement. The other end of the crank arm is actuated by a crankshaft provided with a variable eccentric bearing ranging from O to a maximum required deflection dimension. At an intermediate portion of the crank arm a guide bearing is provided confining such portion of the crank arms movement to longitudinal reciprocating movement thereby 3,518,868 Patented July 7, 1970 translating the variable circular orbital movement at the crankshaft end of the crank arm into a similar opposite orbital movement of the work piece neutral axis, the respective orbital amplitudes being approximately equal when the intermediate guide bearing is located at the mid point between the axis of the crankshaft and neutral axis of the work piece.

The method of the invention is characterized by producing a relative orbital deflection or displacement of longitudinally spaced portions of the work piece about a nominal correct neutral axis independently of any rotation of the work piece per se about its own axis whereby the eccentricity or bending of the work piece will proceed continuously throughout all radial directions relative to the correct neutral axis so that any initial distortion in the work piece will produce a maximum displacement beyond yield point in the direction opposite to such distortion so that when orbiting of the neutral axis is first increased to the yield point and then gradually reduced a straightening action will result.

The mechanical and method aspects of the present invention will be more clearly understood from the following detailed description of a preferred embodiment of the machine and method with reference to the drawings forming a part of this disclosure wherein:

DESCRIPTION OF THE DRAWINGS FIG. 1 FIG. 2 FIG. 3

is a plan view of the straightening machine; is a side elevation of said machine; is an end elevation of said machine;

FIG. 4 is an enlarged sectional view taken along the line 44 of FIG. 1;

FIG. 5 is an enlarged sectional view taken along the line 55 of FIG. 1 and also along the line 55 of FIG. 4;

FIG. 6 is a sectional view taken along the line 66 of FIG. 5;

FIG. 7 is a partially sectioned view taken along the line 77 of FIG. 4;

FIG. 8 is an enlarged fragmentary sectional view taken along the line 8-8 of FIG. 1;

FIG. 9 is an enlarged fragmentary sectional view taken along the line 9-9 of FIG. 1;

FIG. 10 is an enlarged fragmentary view of the clamping mechanism per se shown at the right hand end of FIG. 5;

FIG. 11 is an end view taken along the line 1111 of FIG. 10 (also forming an enlarged fragmentary view) taken along the line 11-41 of FIG. 1;

FIG. 12 is an enlarged fragmentary view of control elements shown at the left hand end of FIG. 1; and

FIG. 13 is a schematic perspective view of the principal operating elements.

Referring to FIG. 13 the basic actuating elements schematically shown include drive motor A, gearing B, crankshaft C, crank arm D, adapted through bearing means not shown to impart a variable orbital movement to the neutral axis of an elongated work piece E rigidly clamped at one end of the crank arm D, the outer ends of the work piece E being retained in spherical bearings P which accommodate angular variation of the work piece axis as required by the orbital movement imparted to the center thereof while restraining such ends from radial movement relative to the axis.

Referring to FIGS. 123 corresponding elements are similarly identified and in addition are shown an actuating power and control unit G for varying the effective eccentricity of the crankshaft and orbital stroke, and a guide bearing H for controlling crank arm movement imparted to the work piece. Further elements illustrated in FIGS. 1-2-3 will be better understood and described following an explanation of certain of the sectional views which most clearly illustrate the working elements and relationships.

With reference to FIGS. 4-5-6, the heart of the method of the present invention lies in imparting an orbital movement to the neutral axis of a work piece (rigidly clamped between jaws which at its maximum equals or exceeds the elastic limit or yield point of a work piece relative to its true neutral axis and in gradually diminishing the amplitude of such orbital path at a rate per cycle related to the allowable tolerance variation of the work piece axis from the nominal true neutral axis; while the heart of mechanism of the invention employed for practicing the method in the preferred embodiment lies in means for imparting a variable orbital path to the crankshaft end 21 of the crank arm D and translating such orbital movement into a similar orbital movement of the jaws 20 through the instrumentality of a guide bearing H accommodating a longitudinal and rocking movement at the center of the crank arm.

Variable displacement for effective crankshaft throw is accomplished by modifying the eccentricity of a crankshaft ring 22 rotatable within bearing 23 in the crankshaft end 21 of the crank arm D through reciprocal movement of shaft 24 and yoke 25 attached to the end thereof moving roller shaft 26 and cam rollers 27, 28 journaled thereon which engage respectively horizontal cam tracks 29 located within the rectangular shaft 30 rigidly connecting annular crankshaft shoulders 31 and cooperating inclined cam tracks 32 extending through the ring 22. The annular rings 31 are rigidly mounted to a driving hub 33 secured to the end of the hollow drive shaft 34 mounted within heavy duty roller bearings 35 and a sleeve bearing 36 within stationary housing 37. An outboard bearing 39 is preferably provided for a shaft extension 39 of the outboard annular crankshaft shoulder 31 in order to provide additional frame support 40 against deflection of the crankshaft assembly during rotation produced by worm gear 41, driven by worm 42, shaft 43, pulley drive 44 and motor A (see FIG. I). The eccentricity of the ring 22 relative to the crankshaft axis which determines the effective throw and orbital path of the crankshaft end 21 is thus established by the position of the rollers 27 and 28 along the respective divergent cam tracks 29 and 32 which are positioned through shaft 24 and rotatable coupling 45 by hydraulic cylinder 46 and piston rod 47 under limit switch control as hereinafter described.

As best shown in FIG. 5 the crank arm D is provided with large rollers 48 mounted on stub shafts 49 extending from either side of the crank arm D engaging guide tracks 50 carried by stationary frame 51, such rollers and guide tracks serving to accommodate longitudinal and rocking movement of the crank arm D producing an effective orbital movement of the center 52 between jaw 20 opposite and substantially equal to the corresponding orbital movement at the crankshaft end of the arm D. As best shown in FIG. 6, bearing blocks 53 carried within rigid box frame elements 54 serve to guide the crank arm and maintain operating alignment of the jaws with the crankshaft.

As best shown in FIGS. 10 and 11 the work piece engaging jaws 20 are secured to a pair of bell crank arms 55a, 55b pivoted on a common central shaft 56 seated in a jaw retaining head 57 mounted on the outer end 58 of the crank arm D. The jaw actuating cylinder mechanism I mounted on side plates 59 includes a piston rod 60 connected to a cam rail 61 on which are installed a pair of actuating cams 62, 63 for engaging shoes 64a, 64b mounted respectively on the bell crank arms 55a, 55b to establish final closed position of the jaws as shown in FIG. 10 upon retraction of the piston 60. Actuation of the cam rail 62 in the opposite direction releases a locking pressure exerted between the shoes and cam surfaces after which the ends 62a and 62b of the earns 62, 63 engage respectively a button 65 mounted on an extension of the bell crank arm 55a and a similar button 66 mounted on an auxiliary bell crank arm 67 pivoted at 68 and having a ball end 69 engaging a slot in the other bell crank arm 55b serving to open respectively the jaws to the dotted line positions indicated at 20a. This mechanism permits precise simultaneous closure of the jaws to an exact position relative to the nominally correct neutral axis 70 of the work piece W.

Referring to FIGS. 8 and 9 spherical bearings 71, 72 are provided in bearing blocks 73, 74 for the respective splined ends of a particular work piece W through suitable adapter sleeves 75, 76 seated within inner race bearing collars 77, 78. The right hand collar 77 shown in FIG. 9 houses an axially slidable shaft 79 having a centering disc 80 attached to the outer end thereof for engaging the centering ring 81 mounted with bearing block 73 on a slide 82 on a fixed frame member 83. Compression spring 84 in the absence of a work piece urges the centering disc 80 into engagement with ring 81 as shown in dotted line at 80a to establish axial alignment of the spherical bearing with the axis of the work piece at the time of loading at which time the slide 82 is retracted by piston rod 98 and the ejection button 85 is extended by compression spring 86 housed within the shaft 79. At the left hand end shown in FIG. 8 the adapter 76 is axially slidable within the sleeve 78 and collar 87 from the full line position shown to a dotted l1ne position 76a and is urged to the latter position by tension springs 88 acting between the collar 87 and an end cap 89 mounted on the end of the adapter. The tension spring 90 acting between a fitting 91 on such end cap and fitting 92 on adjustable slide 93 on a stationary mountlng element 94 in the absence of a work piece urges the adapter 76 within the spherical bearing to the upwardly inclined dotted line position shown on 76b in order to facilitate work piece loading. During such loadmg the work piece (not shown) is inserted within the adapter 76 into abutment with the shaft 95 and the other end is then centered with the tapered sleeve 75 at which time actuation of the piston rod 98 will serve to first extend the springs 88' and then compress the ejector spring 86 and finally compress the spring 84 to the posit1on shown in full line in FIG. 9 where centering disc 80 is out of engagement with ring 81 and free to move with the spherical bearing to the dotted line position shown at 80b as may be required during the straightening actlon.

It will be understood that work pieces of different length may be accommodated and adjusted to an exact desired position relative to the work piece engaging jaws 20 through adjustment of the respective slides 82 and 93 as by a rack 96 and pinion 97 and an adjustment of the elfcctive length of the piston rod 98.

Referring to FIGS. 1, 4 and 12 it will be understood that the orbiting amplitude elfected by hydraulic cylinder 46 through shaft 24 and cam rollers 27, 28 as previously described may be automatically and adjustably controlled through appropriate hydraulic valving (not shown) for regulating the rate of flow to the extending and retracting ends of double acting cylinder 46 including appropriate solenoid actuated valving under the control of limit switches 99 and 100 actuated respectively by stops 101 and 102 carried by the piston rod extension 47, the stop 102 for controlling the maximum eccentricity of the orbital movement being adjustable through adjustment 10-3 with the position indicated by scale 104. In a normal straightening operation the work piece will be manually loaded into the spherical end bearings F. The cylinder I will be actuated under manually or automatic controls to close the jaws 20 on a work piece whereupon the orbit varying mechanism G will be actuated to produce an increasing amplitude until limit switch 100 is actuated and then a decreasing amplitude back to zero at which time limit switch 99 will be actuated. The jaw cylinder I will then be actuated to release the work piece for manual removal. It will be further understood that since actuation of the crank arm D is stopped upon retraction of the cam rollers 27, 28 to their zero amplitude position, the drive motor A, gearing B and crankshaft C may remain in operation during work piece loading and unloading as well as during the straightening operation.

While a particular preferred embodiment of the mechanism and method for carrying out the present invention have been described above in detail, it will be understood that numerous modifications may be resorted to without departing from the scope of the invention as defined in the following claims.

I claim:

1. A machine for straightening production work pieces individually having varying degrees of distortion relative to a neutral axis characterized by means for engaging each work piece at spaced points along said axis, means for producing relative orbital deflection of the work piece axis at said spaced engaging points through the elastic limit of said work piece, and means for gradually reducing the amplitude of said orbital deflection to an extent at least within the elastic limit of said work piece, said respective means operating independently of any rotation of said work piece about its own axis.

2. A straightening machine as set forth in claim 1 wherein said means for producing relative orbital deflection includes a crank arm connectable to said Work piece, and means for moving the work piece connection of said crank arm in a variable orbital path.

3. A straightening machine as set forth in claim 1 wherein said means for producing relative orbital deflection includes a crank arm connectable to said work piece, and means including a crankshaft having a variable eccentric connection to said crank arm for moving the work piece connection of said crank arm in a variable orbital path.

4. A straightening machine as set forth in claim 1 wherein said means for providing relative orbital deflection includes a crank arm connected to said work piece, a crankshaft having a variable eccentric connection to said crank arm, and guide means spaced from said respective crank arm connections for causing the variable eccentricity of said crankshaft to be translated to a variable orbital path for said work piece connection.

5. A straightening machine as set forth in claim 4 wherein said guide means is intermediate said respective crank arm connections.

6. A straightening machine as set forth in claim 3 wherein said craftshafts variable eccentric connection includes a cam actuated radially displaceable crankshaft element.

7. A straightening machine as set forth in claim 3 wherein said crankshafts variable eccentric connection includes a cam actuated radially displaceable crankshaft element, and a radially fixed shaft element forming a reaction element for said cam actuated radially displaceable crankshaft element.

8. A straightening machine as set forth in claim 7 including roller means interacting between said cam actuated and reaction elements.

9. A straightening machine as set forth in claim 8 including means displaceable axially of said crankshaft for positioning said roller means.

10. A straightening machine as set forth in claim 8 including means displaceable axially of said crankshaft for positioning said roller means between positions of maximum and zero displacement of said radially displaceable element, said last means including hydraulic cylinder actuating and control means capable of coordinating the rate of displacement of said radially displaceable element with the rate of rotation of said crankshaft.

11. A straightening machine as set forth in claim 10, and means for continuously rotating said crankshaft during said radial displacement.

12. A straightening machine as set forth in claim 2 including radially fixed end bearings for said work piece.

13. A straightening machine as set forth in claim 3, including radially fixed spherical end bearings for said work piece accommodating axial directional deflection during said relative orbital deflection.

14. A straightening machine as set forth in claim 13, including jaw elements at the work piece engaging end of said crank arm, and means for synchronously moving said jaw elements into work piece engagement automatically centering the neutral axis of said work piece with the axis of said end bearings at a zero eccentric displacement position of said crankshaft.

15. A straightening method for a Work piece having a distorted neutral axis; said method comprising a first step of supporting the work piece, and characterized by the further step of producing independently of any work piece rotation about its own axis relative orbital deflection of the work piece neutral axis at axially spaced points with gradually diminishing amplitude passing through the yield point.

16. A straightening method as set forth in claim 15 including an initial step of increasing the amplitude of said orbital deflection to a predetermined maximum before producing said gradually diminishing amplitude.

17. A straightening method as set forth in claim 15 wherein said relative orbital movement takes place between an intermediate and two outwardly axially spaced points.

18. A straightening method as set forth in claim 17 wherein said outwardly spaced points remain in axial alignment.

References Cited UNITED STATES PATENTS 1,659,181 2/1928 Woods 72389 3,328,995 7/1967 Rohlfs 72-389 3,335,587 8/1967 Blachut 72-389 3,446,054 5/1969 Pridy 72389 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner 

